Electron Microprobe

An electron microprobe (EMP), also known as an electron probe microanalyzer (EPMA) or electron micro probe analyzer (EMPA), is an analytical tool used to non-destructively determine the chemical composition of small volumes of solid materials. It works similarly to a scanning electron microscope: the sample is bombarded with an electron beam, emitting x-rays at wavelengths characteristic to the elements being analyzed. This enables the abundances of elements present within small sample volumes (typically 10-30 cubic micrometers or less) to be determined. The concentrations of elements from boron to plutonium can be measured at levels as low as 100 parts per million (ppm). Recent improvements on EMPAs (e.g. the Cameca SX100 with five oversized PET crystals for trace element analysis) can accurately measure elemental concentrations of approximately 10 ppm.